Apparatus and method to manage interference between communication nodes

ABSTRACT

An apparatus, method and system to control a transmitter power level to manage interference between communication nodes in a communication system. In one embodiment, an apparatus includes a processor and memory including computer program code. The memory and the computer program code are configured to, with the processor, cause the apparatus to receive an interference message including a reported interference characteristic associated with a communication resource employed by an interfered communication node and a reported weighting factor indicating an importance of the communication resource to the interfered communication node. The memory and the computer program code are also configured to, with the processor, cause the apparatus to generate a message for a receiving communication node employing the communication resource, and select a transmitter power level for the message as a function of the reported interference characteristic and the reported weighting factor.

TECHNICAL FIELD

The present invention is directed, in general, to communication systemsand, in particular, to an apparatus, method and system to control atransmitter power level to manage interference between communicationnodes in a communication system.

BACKGROUND

Long term evolution (“LTE”) of the Third Generation Partnership Project(“3GPP”), also referred to as 3GPP LTE, refers to research anddevelopment involving the 3GPP LTE Release 8 and beyond, which is thename generally used to describe an ongoing effort across the industryaimed at identifying technologies and capabilities that can improvesystems such as the universal mobile telecommunication system (“UMTS”).The notation “LTE-A” is generally used in the industry to refer tofurther advancements in LTE. The goals of this broadly based projectinclude improving communication efficiency, lowering costs, improvingservices, making use of new spectrum opportunities, and achieving betterintegration with other open standards.

The evolved universal terrestrial radio access network (“E-UTRAN”) in3GPP includes base stations providing user plane (including packet dataconvergence protocol/radio link control/media access control/physical(“PDCP/RLC/MAC/PHY”) sublayers) and control plane (including a radioresource control (“RRC”) sublayer) protocol terminations towardswireless communication devices such as cellular telephones. A wirelesscommunication device or terminal is generally known as user equipment(also referred to as “UE”). A base station is an entity of acommunication network often referred to as a Node B or an NB.Particularly in the E-UTRAN, an “evolved” base station is referred to asan eNodeB or an eNB. For details about the overall architecture of theE-UTRAN, see 3GPP Technical Specification (“TS”) 36.300 v8.7.0(2008-12), which is incorporated herein by reference. For details of thecommunication or radio resource control management, see 3GPP TS 25.331v.9.1.0 (2009-12) and 3GPP TS 36.331 v.9.1.0 (2009-12), which areincorporated herein by reference.

As wireless radio communication systems such as cellular telephone,satellite, and microwave communication systems become widely deployedand continue to attract a growing number of users, there is a pressingneed to accommodate a large and variable number of communication devicesthat transmit an increasing quantity of data within a fixed spectralallocation and limited transmitter power levels. The increased quantityof data is a consequence of wireless communication devices transmittingvideo information and surfing the Internet, as well as performingordinary voice communications. Such processes are performed whileaccommodating substantially simultaneous operation of a large number ofwireless communication devices.

Cellular communication systems have typically been structured with anarchitecture that enables wireless communication devices such as userequipment to communicate with another user equipment through one or moreintermediary base stations that establish and control communicationlinks or paths between the user equipment. However, directdevice-to-device (“D2D”), mobile-to-mobile (“M2M”), terminal-to-terminal(“T2T”), peer-to-peer (“P2P”) communications is also beginning to bebroadly integrated into cellular communication systems such as LTE/LTE-Acellular communication systems as specified in the 3GPP. Integration ofdirect device-to-device communications enable wireless communicationdevices such as user equipment, mobile devices, terminals, peers, ormachines to communicate over a direct wireless communication link thatuses communication or radio resources of the cellular communicationsystem or network. In this manner, the communication resources areshared by the devices communicating directly with each other withdevices having a communication link to a base station.

Cellular and other wireless communication devices (“communicationnodes”) thus generally share common communication resources includingcommon frequency channels and time slots. As a result, increasing atransmitter power level at one communication node to improve that node'sthroughput and communication quality may cause interference with anothercommunication node such as a neighboring communication node. One of themore problematic issues is how to control a transmitter power level fora communication node operating under an LTE cellular communicationsystem without unfairly producing interference with anothercommunication node. Interference-aware scheduling (“IAS”) is aconventional process in communication systems that makes a tradeoffbetween interference and throughput (“TP”) by choosing a transmitterpower level of a communication node configured to transmit data based ona gain in throughput at the transmitting communication node against aloss of throughput at other communication nodes (such as interferedcommunication nodes). Interference-aware scheduling may use a utilityfunction to relate the gain of throughput at one communication node tothe loss of throughput at another communication node.

A conventional utility function does not take into account that the samethroughput is much more valuable to a “resource-poor” communication nodecompared to a “resource-rich” communication node, thereby disregarding“fairness” in allocation of sparse communication resources. Thus, thereis need for interference-aware scheduling that takes environmentalcircumstances of each communication node into account that avoids thedeficiencies of current communication systems.

SUMMARY OF THE INVENTION

These and other problems are generally solved or circumvented, andtechnical advantages are generally achieved, by embodiments of thepresent invention, which include an apparatus, method and system tocontrol a transmitter power level to manage interference betweencommunication nodes in a communication system. In one embodiment, anapparatus includes a processor and memory including computer programcode. The memory and the computer program code are configured to, withthe processor, cause the apparatus to receive an interference messageincluding a reported interference characteristic associated with acommunication resource employed by an interfered communication node anda reported weighting factor indicating an importance of thecommunication resource to the interfered communication node. The memoryand the computer program code are also configured to, with theprocessor, cause the apparatus to generate a message for a receivingcommunication node employing the communication resource, and select atransmitter power level for the message as a function of the reportedinterference characteristic and the reported weighting factor.

In another embodiment, an apparatus includes a processor and memoryincluding computer program code. The memory and the computer programcode are configured to, with the processor, cause the apparatus todetermine an interference characteristic associated with a communicationresource employed by the apparatus, and determine a weighting factorindicating an importance of the communication resource to the apparatus.The memory and the computer program code are also configured to, withthe processor, cause the apparatus to format the interferencecharacteristic and the weighting factor into an interference message fortransmission to a communication node.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter, which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures or processes for carrying outthe same purposes of the present invention. It should also be realizedby those skilled in the art that such equivalent constructions do notdepart from the spirit and scope of the invention as set forth in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention, and the advantagesthereof, reference is now made to the following descriptions taken inconjunction with the accompanying drawings, in which:

FIGS. 1 and 2 illustrate system level diagrams of embodiments ofcommunication systems including a base station and wirelesscommunication devices that provide an environment for application of theprinciples of the present invention;

FIGS. 3 and 4 illustrate system level diagrams of embodiments ofcommunication systems including wireless communication systems thatprovide an environment for application of the principles of the presentinvention;

FIG. 5 illustrates a system level diagram of an embodiment of acommunication element of a communication system for application of theprinciples of the present invention;

FIG. 6 illustrates a system level diagram of an embodiment of acommunication system including communication nodes that provides anenvironment for the application of the principles of the presentinvention;

FIG. 7 illustrates a flowchart of an embodiment of a method of selectinga transmitter power level by a communication node according to theprinciples of the present invention;

FIG. 8 illustrates a flowchart of an embodiment of a method ofdetermining a weighting factor by a communication node in accordancewith the principles of the present invention;

FIG. 9 illustrates a flowchart of an embodiment of generating aninterference message by a communication node in accordance with theprinciples of the present invention; and

FIG. 10 illustrates a flowchart of an embodiment of a method ofselecting a transmitter power level for a message by a communicationnode that may interfere with another communication node in accordancewith the principles of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently preferred embodiments arediscussed in detail below. It should be appreciated, however, that thepresent invention provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention. Inview of the foregoing, the present invention will be described withrespect to exemplary embodiments in a specific context of an apparatus,method and system to control a transmitter power level to manageinterference with between communication nodes in a communication system.The apparatus, method and system are applicable, without limitation, toany communication system including existing and future 3GPP technologiessuch as UMTS, LTE, and its future variants such as 4th generation (“4G”)communication systems.

Turning now to FIG. 1, illustrated is a system level diagram of anembodiment of a communication system including a base station 115 andwireless communication devices (e.g., user equipment) 135, 140, 145 thatprovides an environment for application of the principles of the presentinvention. The base station 115 is coupled to a public switchedtelephone network (not shown). The base station 115 is configured with aplurality of antennas to transmit and receive signals in a plurality ofsectors including a first sector 120, a second sector 125, and a thirdsector 130, each of which typically spans 120 degrees. The three sectorsor more than three sectors are configured per frequency, and one basestation 115 can support more than one frequency. Although FIG. 1illustrates one wireless communication device (e.g., wirelesscommunication device 140) in each sector (e.g. the first sector 120), asector (e.g. the first sector 120) may generally contain a plurality ofwireless communication devices. In an alternative embodiment, a basestation 115 may be formed with only one sector (e.g. the first sector120), and multiple base stations may be constructed to transmitaccording to co-operative multi-input/multi-output (“C-MIMO”) operation,etc.

The sectors (e.g. the first sector 120) are formed by focusing andphasing radiated signals from the base station antennas, and separateantennas may be employed per sector (e.g. the first sector 120). Theplurality of sectors 120, 125, 130 increases the number of subscriberstations (e.g., the wireless communication devices 135, 140, 145) thatcan simultaneously communicate with the base station 115 without theneed to increase the utilized bandwidth by reduction of interferencethat results from focusing and phasing base station antennas. While thewireless communication devices 135, 140, 145 are part of a primarycommunication system, the wireless communication devices 135, 140, 145and other devices such as machines (not shown) may be a part of asecondary communication system to participate in, without limitation,D2D and machine-to-machine communications or other communications.Additionally, the wireless communication devices 135, 140, 145 may formcommunication nodes along with other devices in the communicationsystem.

Turning now to FIG. 2, illustrated is a system level diagram of anembodiment of a communication system including a base station 210 andwireless communication devices (e.g., user equipment) 260, 270 thatprovides an environment for application of the principles of the presentinvention. The communication system includes the base station 210coupled by communication path or link 220 (e.g., by a fiber-opticcommunication path) to a core telecommunications network such as publicswitched telephone network (“PSTN”) 230. The base station 210 is coupledby wireless communication paths or links 240, 250 to the wirelesscommunication devices 260, 270, respectively, that lie within itscellular area 290.

In operation of the communication system illustrated in FIG. 2, the basestation 210 communicates with each wireless communication device 260,270 through control and data communication resources allocated by thebase station 210 over the communication paths 240, 250, respectively.The control and data communication resources may include frequency andtime-slot communication resources in frequency division duplex (“FDD”)and/or time division duplex (“TDD”) communication modes. While thewireless communication devices 260, 270 are part of a primarycommunication system, the wireless communication devices 260, 270 andother devices such as machines (not shown) may be a part of a secondarycommunication system to participate in, without limitation,device-to-device and machine-to-machine communications or othercommunications. Additionally, the wireless communication devices 260,270 may form communication nodes along with other devices in thecommunication system.

Turning now to FIG. 3, illustrated is a system level diagram of anembodiment of a communication system including a wireless communicationsystem that provides an environment for the application of theprinciples of the present invention. The wireless communication systemmay be configured to provide evolved UMTS terrestrial radio accessnetwork (“E-UTRAN”) universal mobile telecommunications services. Amobile management entity/system architecture evolution gateway (“MME/SAEGW,” one of which is designated 310) provides control functionality foran E-UTRAN node B (designated “eNB,” an “evolved node B,” also referredto as a “base station,” one of which is designated 320) via an S1communication link (ones of which are designated “S1 link”). The basestations 320 communicate via X2 communication links (ones of which aredesignated “X2 link”) The various communication links are typicallyfiber, microwave, or other high-frequency communication paths such ascoaxial links, or combinations thereof.

The base stations 320 communicate with wireless communication devicessuch as user equipment (“UE,” ones of which are designated 330), whichis typically a mobile transceiver carried by a user. Thus, thecommunication links (designated “Uu” communication links, ones of whichare designated “Uu link”) coupling the base stations 320 to the userequipment 330 are air links employing a wireless communication signalsuch as, for example, an orthogonal frequency division multiplex(“OFDM”) signal. While the user equipment 330 are part of a primarycommunication system, the user equipment 330 and other devices such asmachines (not shown) may be a part of a secondary communication systemto participate in, without limitation, D2D and machine-to-machinecommunications or other communications. Additionally, the user equipment330 may form a communication node along with other devices in thecommunication system.

Turning now to FIG. 4, illustrated is a system level diagram of anembodiment of a communication system including a wireless communicationsystem that provides an environment for the application of theprinciples of the present invention. The wireless communication systemprovides an E-UTRAN architecture including base stations (one of whichis designated 410) providing E-UTRAN user plane (packet data convergenceprotocol/radio link control/media access control/physical) and controlplane (radio resource control) protocol terminations towards wirelesscommunication devices such as user equipment 420 and other devices suchas machines 425 (e.g., an appliance, television, meter, etc.). The basestations 410 are interconnected with X2 interfaces or communicationlinks (designated “X2”) and are connected to the wireless communicationdevices such as user equipment 420 and other devices such as machines425 via Uu interfaces or communication links (designated “Uu”). The basestations 410 are also connected by S1 interfaces or communication links(designated “S1”) to an evolved packet core (“EPC”) including a mobilemanagement entity/system architecture evolution gateway (“MME/SAE GW,”one of which is designated 430). The S1 interface supports a multipleentity relationship between the mobile management entity/systemarchitecture evolution gateway 430 and the base stations 410. Forapplications supporting inter-public land mobile handover, inter-eNBactive mode mobility is supported by the mobile management entity/systemarchitecture evolution gateway 430 relocation via the S1 interface.

The base stations 410 may host functions such as radio resourcemanagement. For instance, the base stations 410 may perform functionssuch as Internet protocol (“IP”) header compression and encryption ofuser data streams, ciphering of user data streams, radio bearer control,radio admission control, connection mobility control, dynamic allocationof communication resources to user equipment in both the uplink and thedownlink, selection of a mobility management entity at the userequipment attachment, routing of user plane data towards the user planeentity, scheduling and transmission of paging messages (originated fromthe mobility management entity), scheduling and transmission ofbroadcast information (originated from the mobility management entity oroperations and maintenance), and measurement and reporting configurationfor mobility and scheduling. The mobile management entity/systemarchitecture evolution gateway 430 may host functions such asdistribution of paging messages to the base stations 410, securitycontrol, termination of user plane packets for paging reasons, switchingof user plane for support of the user equipment mobility, idle statemobility control, and system architecture evolution bearer control. Theuser equipment 420 and machines 425 receive an allocation of a group ofinformation blocks from the base stations 410.

Additionally, the ones of the base stations 410 are coupled a home basestation 440 (a device), which is coupled to devices such as userequipment 450 and/or machines (not shown) for a secondary communicationsystem. The base station 410 can allocate secondary communication systemresources directly to the user equipment 450 and machines, or to thehome base station 440 for communications (e.g., local or D2Dcommunications) within the secondary communication system. The secondarycommunication resources can overlap with communication resourcesemployed by the base station 410 to communicate with the user equipment420 within its serving area. For a better understanding of home basestations (designated “HeNB”), see 3 GPP TS 32.781 v.9.1.0 (2010-03),which is incorporated herein by reference. While the user equipment 420and machines 425 are part of a primary communication system, the userequipment 420, machines 425 and home base station 440 (communicatingwith other user equipment 450 and machines (not shown)) may be a part ofa secondary communication system to participate in, without limitation,D2D and machine-to-machine communications or other communications.Additionally, the user equipment 420 and machines 425 may formcommunication nodes along with other devices in the communicationsystem.

Turning now to FIG. 5, illustrated is a system level diagram of anembodiment of a communication element 510 of a communication system forapplication of the principles of the present invention. Thecommunication element or device 510 may represent, without limitation, abase station, a wireless communication device (e.g., a subscriberstation, terminal, mobile station, user equipment, machine), a networkcontrol element, a communication node, or the like. Additionally, thecommunication element or device 510 may form a communication node alongwith other devices in the communication system. When the communicationelement or device 510 represents a communication node such as a userequipment, the user equipment may be configured to communicate withanother communication node such as another user equipment employing oneor more base stations as intermediaries in the communication path(referred to as cellular communications). The user equipment may also beconfigured to communicate directly with another user equipment withoutdirect intervention of the base station in the communication path. Thecommunication element 510 includes, at least, a processor 520, memory550 that stores programs and data of a temporary or more permanentnature, an antenna 560, and a radio frequency transceiver 570 coupled tothe antenna 560 and the processor 520 for bidirectional wirelesscommunications. The communication element 510 may be formed with aplurality of antennas to enable a multiple-input multiple output(“MIMO”) mode of operation. The communication element 510 may providepoint-to-point and/or point-to-multipoint communication services.

The communication element 510, such as a base station in a cellularcommunication system or network, may be coupled to a communicationnetwork element, such as a network control element 580 of a publicswitched telecommunication network (“PSTN”). The network control element580 may, in turn, be formed with a processor, memory, and otherelectronic elements (not shown). The network control element 580generally provides access to a telecommunication network such as a PSTN.Access may be provided using fiber optic, coaxial, twisted pair,microwave communications, or similar link coupled to an appropriatelink-terminating element. A communication element 510 formed as awireless communication device is generally a self-contained deviceintended to be carried by an end user.

The processor 520 in the communication element 510, which may beimplemented with one or a plurality of processing devices, performsfunctions associated with its operation including, without limitation,precoding of antenna gain/phase parameters (precoder 521), encoding anddecoding (encoder/decoder 523) of individual bits forming acommunication message, formatting of information, and overall control(controller 525) of the communication element, including processesrelated to management of communication resources (resource manager 528).Exemplary functions related to management of communication resourcesinclude, without limitation, hardware installation, traffic management,performance data analysis, tracking of end users and equipment,configuration management, end user administration, management ofwireless communication devices, management of tariffs, subscriptions,security, billing and the like. For instance, in accordance with thememory 550, the resource manager 528 is configured to allocate primaryand second communication resources (e.g., time and frequencycommunication resources) for transmission of voice communications anddata to/from the communication element 510 and to format messagesincluding the communication resources therefor in a primary andsecondary communication system. Additionally, the resource manager 528may manage interference between communication nodes in the primary andsecondary communication system.

The execution of all or portions of particular functions or processesrelated to management of communication resources may be performed inequipment separate from and/or coupled to the communication element 510,with the results of such functions or processes communicated forexecution to the communication element 510. The processor 520 of thecommunication element 510 may be of any type suitable to the localapplication environment, and may include one or more of general-purposecomputers, special purpose computers, microprocessors, digital signalprocessors (“DSPs”), field-programmable gate arrays (“FPGAs”),application-specific integrated circuits (“ASICs”), and processors basedon a multi-core processor architecture, as non-limiting examples.

The transceiver 570 of the communication element 510 modulatesinformation on to a carrier waveform for transmission by thecommunication element 510 via the antenna(s) 560 to anothercommunication element. The transceiver 570 demodulates informationreceived via the antenna(s) 560 for further processing by othercommunication elements. The transceiver 570 is capable of supportingduplex operation for the communication element 510.

The memory 550 of the communication element 510, as introduced above,may be one or more memories and of any type suitable to the localapplication environment, and may be implemented using any suitablevolatile or nonvolatile data storage technology such as asemiconductor-based memory device, a magnetic memory device and system,an optical memory device and system, fixed memory, and removable memory.The programs stored in the memory 550 may include program instructionsor computer program code that, when executed by an associated processor,enable the communication element 510 to perform tasks as describedherein. Of course, the memory 550 may form a data buffer for datatransmitted to and from the communication element 510. Exemplaryembodiments of the system, subsystems, and modules as described hereinmay be implemented, at least in part, by computer software executable byprocessors of, for instance, the wireless communication device and thebase station, or by hardware, or by combinations thereof. As will becomemore apparent, systems, subsystems and modules may be embodied in thecommunication element 510 as illustrated and described herein.

Turning now to FIG. 6, illustrated is a system level diagram of anembodiment of a communication system including communication nodes(“CN”) that provides an environment for the application of theprinciples of the present invention. A first communication node 605 hasdata to transmit to a second communication node 610 via a communicationlink 615. On a given communication or radio resource, the firstcommunication node 605 achieves more throughput by using a highertransmitter power level. A higher transmitter power level, however, mayincrease unwanted interference via communication links 625, 635 to thirdand fourth communication nodes 620, 630, respectively.

As introduced herein, interference-aware scheduling communication nodesselect a transmitter power level to augment (e.g., maximize) a utilityfunction that takes both the communication node's own throughput gainand losses at another communication node (referred to as an interferedcommunication node such as a nearby communication node) into account,including consideration of communication circumstances at the nearbycommunication node. The transmitter power level may be chosen incombination with choosing other communication resources. For example,depending on circumstances, the first communication node 605 mightdecide not to transmit at all because losses at the nearby communicationnode may outweigh its own gain. The first communication node 605 mighttransmit at the highest possible transmitter power level if the gain inthroughput outweighs losses at the nearby communication node. The firstcommunication node 605 might transmit at a mid-range transmitter powerlevel to strike a balance between its own gain and losses at the nearbycommunication node.

In general, a utility function in interference-aware scheduling mayinclude the sum of throughputs at each communication node. Anotherexample for a utility function is the sum of a logarithm of thethroughput at each communication node. Throughput may be determined asthe number of bits successfully transmitted in a given time (e.g., inbits per second). Since the transmission of bits may involveinterleaving, coding, retransmissions or other techniques that requiresome duration of time, it may be preferable to use an estimate ofthroughput instead. Throughput may be estimated based on asignal-to-noise plus interference ratio (“SNIR”) and a bandwidth (“BW”).For example, an estimated throughput TP_(est) of a communication orradio resource with a bandwidth may be estimated as a channel capacityTP_(est)=BW log₂(1+SNIR), and estimation may be performed by looking upthe estimated throughput TP_(est) for a given value of SNIR from atable. A communication node may determine a communication resourcethroughput that is achieved on a given communication resource, forexample, a communication channel or sub-band. A communication node maydetermine a total throughput that is achieved on all communication orradio resources in use by the communication node.

The communication or radio environment experienced by nearbycommunication nodes can differ substantially. For example, onecommunication node may be in a more crowded or sparsely populatedlocation than its nearby communication nodes. A line-of-sight interferermay block part of the communication band locally, especially anindustrial, scientific and medical (“ISM”) radio band (e.g., a band usedby a wireless local area network (“WLAN”)). A communication node mayserve a different number of users than a nearby communication node.

As introduced herein, the interference-aware scheduling utility functiontakes into account that a same throughput may be much more valuable to a“resource-poor” communication node than to a “resource-rich”communication node, and thereby takes into account environmentalcircumstances of both communication nodes. Improving “fairness” indistribution of communication resources (including a transmitter powerlevel associated with the resource), which is harder to achieve thansimply maximizing a summed throughput, requires that a communicationnode be aware of environmental circumstances at a nearby communicationnode. For example, a throughput gain or loss of ten kilobits per second(“kbps”) is less important to a communication node that is currentlyable to transmit 1000 kbps to a single user than to anothercommunication node achieving only 100 kbps that are shared among threecommunication links.

An improved interference-aware scheduling solution can be configured touse a reasonable amount of signaling. The communication nodes operatingin nearby communication networks may be unsynchronized and thus mayrequire temporary resynchronization to receive environmental reports.The interference-aware scheduling signaling is preferably tied to thecommunication resource (e.g., a subband, a time or a frequency slot) inquestion. A “bulk” report that bundles data from many subbands may belost due to independent interference on a reporting subband.

It is further desirable for interference-aware scheduling signaling notto rely on the identities of reporting communication nodes. For example,a typical media access control (“MAC”) address uses 48 bits. The actualpayload data of a one communication resource report can be much smaller.When orthogonal communication resources are used to enable the receptionof multiple simultaneous interference-aware scheduling signalingreports, the cost for transmitting one bit increases accordingly.

Thus, in the interference-aware scheduling process introduced herein,communication nodes broadcast information about interference status on acommunication resource such as an uplink shared channel. A weightingfactor is reported by potentially interfered communication nodes thatindicates the “importance” of a communication resource. For instance,the communication resource may be more important relative to anothercommunication resource, if it has a high signal-to-noise plusinterference ratio, or conveys more information. A communicationresource may be more important to a communication node than to anothercommunication node, if the communication node has less communication orradio resources available to choose from, is deployed in a more crowdedcommunication environment or suffers from a higher level ofinterference, for example. A communication resource may be moreimportant if it is used for traffic with a higher priority, for example,voice over Internet protocol or streaming video traffic that hasstringent requirements on latency. A transmitting communication nodepredicts interference it causes to nearby communication nodes bytransmitting on the same communication resource. The transmittingcommunication node chooses a transmitter power level for a “fair”compromise between its own communication gain and others' losses, whichis a cooperative arrangement. A “fair” compromise depends onenvironmental circumstances of the involved communication nodes. Autility function may be employed wherein throughput gained by atransmitting communication node and throughput lost by interferedcommunication nodes are not equally weighted.

A flexible spectrum usage (“FSU”) priority scheme is an example of aninterference management scheme. Another interference management schemeis referred to as resource trading as described in IEEE Standard802.16h, entitled “Part 16: Air Interface for Fixed Broadband WirelessAccess Systems—Improved Coexistence Mechanisms for License-ExemptOperation,” dated Jul. 30, 2010. A further interference managementscheme is decentralized communication resource coordination to improvefairness as described in a publication entitled “Cognitive WirelessCommunication Networks,” by Ekram Hossain, et al., ISBN978-0-387-68830-5, Springer 2007, and in a publication entitled“Distributed Spectrum Allocation via Local Bargaining,” by Cao, et al.,IEEE SECON 2005 proceedings. Interference-aware scheduling, in general,implements distributed communication resource allocation schemes, forexample, as described in a publication entitled “Distributed ResourceAllocation Schemes,” by David A. Schmidt, et al., IEEE Signal ProcessingMagazine, vol. 26, issue 5, September 2009 Additionally, an applicationrelated to the interference reporting is disclosed in PCT ApplicationNo. PCT/CN2010/076867, entitled Method and Apparatus forInterference-Aware Wireless Communications,” by Nentwig, et al., filedSep. 14, 2010. The aforementioned references are incorporated herein byreference.

As introduced herein, an interference-aware scheduling process at acommunication node that is prepared to transmit (also referred to as a“transmitting communication node”) employs general interference-awarescheduling that includes a weighting factor that accounts for anenvironmental communication circumstance at another (e.g., nearby orneighboring) communication node (also referred to as an “interferedcommunication node”). The transmitting communication node, such as thefirst communication node 605 illustrated in FIG. 6, receives aninterference message including reported interference characteristicssuch as a reported received signal strength and a reportednoise-and-interference level, and a reported weighting factor at aninterfered communication node such as the third communication node 620.The transmitting communication node may determine a transmitter powerlevel “P” to augment (e.g., maximize) a utility function u(P) dependingon these factors and over a transmitter power level range. Theinterference message including the reported received signal strength,the reported noise-and-interference level, and the reported weightingfactor may be transmitted by the interfered communication node or by abase station.

A utility function may relate the effect of transmitter power level “P”between several communication nodes. In one example, a fixed transmitterpower level may be divided between a set of communication or radioresources to lessen (e.g., minimize) a reduction of throughput atseveral interfered communication nodes. The reduction of throughput ateach interfered communication node may be weighted with a weightingfactor received in an interference message from the interferedcommunication node. In another example, the utility function alsoincludes the throughput achieved by the transmitting communication node.The utility function may relate throughput achieved by the transmittingcommunication node to a loss of throughput at an interferedcommunication node. The utility function may select the transmit powerlevel to augment (e.g., maximize) the utility function, in other words,balance the loss of throughput at the interfered communication node withthe throughput gained by the transmitting communication node. An examplefor a utility function in interference-aware scheduling is the sum ofweighted throughputs at each communication node. Another example for autility function is the sum of a logarithm of each weighted throughputat the communication nodes. Another example for a utility function isthe sum of weighted logarithms of each throughput at the communicationnodes.

The transmitting communication node may also include a weighting factor(a local weighting factor) that reflects its own communicationcircumstance in its determination of interference-aware scheduling. Thetransmitting communication node may multiply its own throughput withweighting factor and include it as a term in the utility function. Thetransmitting communication node may also compute a predicted receivedsignal strength and a predicted noise-and-interference level in itsdetermination of its own weighting factor in an interference-awarescheduling utility function. The process may be extended to multiplecommunication resources such as multiple time and frequency slots. Thetransmitting communication node may select a set of communicationresources for transmission and determine a transmitter power level foreach communication resource to augment (e.g., maximize) a utilityfunction that depends on all of the communication resources in the setand over a transmitter power level range.

When a transmitter power level is changed from a previous transmitterpower level, it can be expected that an interfered communication node'sreported weighting factor will also change in the next reporting rounddue to the resulting change in interference. To mitigate this effect,large changes in transmitter power level can be limited. A change in atransmitter power level at a transmitting communication node can belimited depending on a weighting factor at an interfered communicationnode. The limitation optionally can be made over a time interval whenthe reported weighting factor exceeds a predetermined threshold. Thelimitation of the change in transmitter power level can be applied whenat least one reported weighting factor out of a plurality of receivedreports exceeds the predetermined threshold.

Alternatively, the weighting factor can be recalculated depending on theconsidered transmitter power level. This is possible since informationthat was used by the interfered communication node to calculate itsreported weighting factor is available at the transmitting communicationnode. A solution may include knowing its own contribution tointerference reported by the interfered communication node (see, e.g.,PCT Application No. PCT/CN2010/076867). The utility function depends ona calculated weighting factor at the interfered communication node,which can be determined by adjusting the reported weighting factor ofthe interfered communication node with the reported interferencecharacteristics such as the reported received signal strength and thereported noise-and-interference level, and the transmitter power levelat the transmitting communication node.

Turning now to FIG. 7, illustrated is a flowchart of an embodiment of amethod of selecting a transmitter power level by a communication node(e.g., the first communication node 605 illustrated in FIG. 6) accordingto the principles of the present invention. The communication node thatis prepared to transmit a message (also referred to as a “transmittingcommunication node”) selects a transmitter power level according to aninterference-aware scheduling utility function that accounts forinterference with another communication node (e.g., an “interferedcommunication node” such as a nearby or neighboring communication node)including characteristics of communication resources to an intendedreceiving communication node and to the interfered communication nodefor which communication may be affected.

The process starts a step or module 700. In a step or module 705, thecommunication node that is preparing to transmit a message receives aninterference message “M” for a communication resource depending on theinterfered communication node's reported interference characteristicssuch as a reported received signal strength S_(interferedrep) and areported noise-and-interference level N_(interferedrep), and a reportedweighting factor W_(interferedrep). The reported weighting factorW_(interferedrep) indicates an importance of the communication resourceto the interfered communication node. As an example, the interferencemessage may originate from the third communication node 620 illustratedin FIG. 6, or may be transmitted from a base station. In a step ormodule 710, the transmitting communication node determines anoise-and-interference level N_(interfered)(P_(r)) at the interferedcommunication node as a function of the transmitting communication nodetransmitter power level range P_(r) for the respective communicationresource such as a time and frequency slot. The noise-and-interferencelevel at the interfered communication node may be corrected for pasttransmission activity of the transmitting communication node 605 thatcontributed to the interference message describing the interferedcommunication node's communication interference characteristics.Additionally, the transmitting communication node may determine areceived signal strength S_(interfered) at the interfered communicationnode for the respective communication resource. The received signalstrength S_(interfered) may be determined as equal to the reportedreceived signal strength S_(interferedrep) in the interference message.

In a step or module 715, a throughput TP_(interfered) for the interferedcommunication node is predicted by the transmitting communication nodeas a function of the transmitter power level range P_(r) that affectsthe noise-and-interference level N_(interfered)(P_(r)) at the interferedcommunication node, and the interfered communication node's reportedreceived signal strength S_(interferedrep). In one embodiment, thethroughput TP_(interfered) is predicted as TP_(interfered)=BWlog₂(1+S_(interfered)/N_(interfered)(P_(r))), where all variables are inlinear units and BW is a bandwidth of a communication resource. Thenoise-and-interference level N_(interfered)(P_(r)) at the interferedcommunication node may be predicted asN_(interfered)(P_(r))=N_(interferedrep) (P_(r)−P_(prev))/L, where L is apath loss estimate, and P_(prev) is a transmitter power level of thetransmitting communication node at an earlier time interval, duringwhich the interfered communication node determined the interferencecharacteristics.

The prediction may be based on a predetermined throughput versussignal-to-noise plus interference (“SNIR”) function (e.g., the functionlog(1+SNIR), which may be limited to the SNIR range [−3 decibels (“dB”),25 dB]). In a step or module 720, the transmitting communication nodeestimates a quality parameter such as a received signal strength S_(own)_(—) _(link) at the intended receiving communication node (e.g., thesecond communication node 610 illustrated in FIG. 6) using a path-lossestimate. A path loss estimate L may be obtained by relating a detectedpower level P_(det) of a known signal feature, such as a pilot tone,reference symbol, preamble, synchronization signal or the like to aknown transmitter power level P_(src) of the feature. The transmitterpower level may be predetermined or encoded into a message such as abroadcast message, for example. The path loss estimate may be calculatedas L=P_(src)/P_(det), in linear units.

In a step or module 725, the transmitting communication node predicts aquality parameter such as a noise-and-interference level N_(own) _(—)_(link) at the intended receiving communication node (e.g., based on areceived noise-and-interference level report such as a channel qualityindicator (“CQI”)). In a step or module 730, the transmittingcommunication node predicts a throughput TP_(own) _(—) _(link) to theintended receiving communication node as a function of the transmitterpower level range P_(r), using the signal strength andnoise-and-interference level predictions. In a step or module 735, thetransmitting communication node determines a weighting factor W_(own)_(—) _(link) for the communication link to the intended receivingcommunication node as a function of its own throughput, which depends onthe transmitter power level range. The weighting factor W_(own) _(—)_(link) indicates the relative importance to the transmittingcommunication node of its own throughput achieved with the communicationresource. The weighting factor in general may be limited to the rangefrom zero to one.

In a step or module 740, the transmitting communication node determinesa weighting factor W_(interfered) for the interfered communication node,indicating the relative importance of throughput by the interferedcommunication node on the communication resource. The weighting factorW_(interfered) of the interfered communication node may depend on itsthroughput TP_(interfered), the reported weighting factorW_(interferedrep) and the transmitter power level range. In oneembodiment, the interfered weighting factor W_(interfered) equals thereported weighting factor W_(interferedrep).

In a step or module 745, the transmitting communication node prepares autility function u(P) that depends on the predicted throughput TP_(own)_(—) _(link) of the communication link to the intended receivingcommunication node, the predicted throughput TP_(interfered) of theinterfered communication link to the interfered communication node, theweighting factor W_(own) _(—) _(link) of the communication link to theintended receiving communication node, and the weighting factorW_(interfered) of the interfered communication link to the interferedcommunication node, all of which are a function of the transmitter powerlevel range P_(r) of the transmitting communication node. In otherwords, the transmitting communication node applies the weighting factorW_(own) _(—) _(link) of the communication link to the intended receivingcommunication node to the predicted throughput TP_(own) _(—) _(link) andthe weighting factor W_(interfered) of the interfered communication linkto the interfered communication node to the predicted throughputTP_(interfered).

If other communication nodes experience interference, then aninterference message is received from each interfered communicationnode, and an individual weighting factor is determined for eachinterfered communication node. An example for a utility function is:

U(P _(r))=TP _(own) _(—) _(link)(P _(r))W _(own) _(—) _(link) +sum_(j=(all interfered nodes))(TP _(interfered,j) W _(interfered,j)),

wherein the sum is iterated using index j over all interferedcommunication nodes. Another example for a utility function is:

U(P _(r))=log(TP _(own) _(—) _(link)(P _(r))W _(own) _(—) _(link))+sum_(j=(all interfered nodes)){log(TP _(interfered,j) W _(interfered,j))}.

In a step or module 750, the transmitting communication node selects atransmitter power level P to augment (e.g., maximize) the utilityfunction u(P). In one embodiment, an exhaustive search is performed tomaximize the utility function u(P) over the transmitter power levelrange (e.g., in 0.5 dB steps of transmitter power level). In analternative embodiment, the utility function u(P) is maximized using ananalytic technique. In a step or module 755, the transmittingcommunication node uses the selected transmitter power level P totransmit a message on the respective communication resource to theintended receiving communication node and the method ends in step ormodule 760.

At a nearby communication node which may be subject to interference(again, an interfered communication node), the weighting factor may bedetermined for a communication resource in agreement with a constraintfunction. The interfered communication node determines for thecommunication resource interference characteristics such as a signalstrength and a noise-and-interference level, and transmits, in aninterference message, a weighting factor, a signal strength, and asignal-to-noise plus interference ratio. The weighting factor may bebased on a ratio of a throughput measure on a communication resource toa summed throughput measure on a set of communication resources.

The constraint function for the weighting factor may depend on a numberof connected communication nodes. The constraint function may constrainweighting factors on multiple communication resources. For example, theconstraint function may sum all reported weights on all communicationresources, and may be limited to all weights with a magnitude less thana threshold level, such as a threshold level of one. The constraintfunction may be dependent on a number of connected communication nodes,and may be employed to constrain a plurality of respective weightingfactors for a plurality of communication resources. An example for aconstraint function is sum_(j=all used radio resources)(W_(j))<=1, whereW_(j) is the weighting factor of communication or radio resource j andindex j iterates over all communication or radio resources. A constraintfunction may be required by a radio standard, for example, to ensurefair reporting by all communication nodes.

In interference-aware scheduling, the intent is that the utilityfunction balances gains and losses with fairness among communicationnodes. As introduced herein, weighting factors “fairly” reflect theimportance of throughput associated with a communication resource to acommunication node, which may differ because the environmentalcircumstances of each communication node may be different. Again, theimportance may reflect a bandwidth availability associated with thecommunication node. Based on the utility function, a transmitter powerlevel is chosen.

If an interfered communication node has acquired only a small number ofcommunication resources, the “importance” of the communication resourcescan depend strongly on the transmitter power level employed by thetransmitting communication node. For example, a weighting factorfunction (as described hereinbelow with reference to FIG. 8) may bedesigned to ensure (e.g., guarantee) each communication link a minimumthroughput. If so, the importance (indicated by the weighting factor) ofa communication resource will increase strongly with additionalinterference once that communication node's throughput falls below alimit. For example, a communication node that does not achieve apredetermined minimum throughput may be allowed to select acommunication or radio resource and transmit a predetermined maximumvalid weighting factor.

This can be taken into account by predicting (at the transmittingcommunication node) how the weighting factor at the interferedcommunication node will change with the transmitter power level at thetransmitting communication node. For example, using a suitable weightingfactor and knowing its own contribution to the reported interference,the transmitting communication node can back-trace the reportedinterference calculation, and thereby predict the next round's reportedweighting factor for any choice of transmitter power level.

Alternatively, a change in a weighting factor at an interferedcommunication node can be disregarded. If so, the maximum increase intransmitter power level on a communication resource can be limited,wherein the interference to the interfered communication node is knownto happen. This limits overshooting a change in transmitter power level.For example, the transmitting communication node may increase itstransmitter power level to reduce a level of interference to acommunication node that is intended to receive its message. As a result,the interference such as reported by another communication node (e.g.,an interfered communication node) increases in the next round ofcalculation. The transmitting communication node is then forced toreduce its transmitter power level, illustrating the possibility ofinstability in the process of calculating a transmitter power level.

The question of stability in setting a transmitter power level relatesto robustness of interference-aware scheduling and related communicationprocesses in a highly loaded communication system. The question ofstability can be addressed by a system designer once a communicationsystem simulator is available. The embodiments presented herein predictthe weighting factor of the interfered communication node resulting as afunction of a transmitter power level range at the transmittingcommunication node in the augmentation (e.g., optimization) of a utilityfunction. In an exemplary embodiment, the dependency of the weightingfactor at the interfered communication node on the transmitter powerlevel range (see, e.g., step or module 740) may be omitted, and thisdependency may be set as a constant.

Turning now to FIG. 8, illustrated is a flowchart of an embodiment of amethod of determining a weighting factor by a communication node inaccordance with the principles of the present invention. From theperspective of the transmitting communication node, the method ofdetermining the weighting factor may be implemented in accordance withrespect to step or module 735 illustrated and described with respect toFIG. 7. The method of determining the weighting factor may be repeatedover a transmitter power level range. From the perspective of theinterfered communication node, the method of determining the weightingfactor may be implemented in accordance with respect to step or module915 illustrated and described with respect to FIG. 9. For the purpose ofclarity and in the spirit of an exemplary embodiment, the method thatfollows will be described from the perspective of a transmittingcommunication node to a receiving communication node. Those skilled inthe art, however, should understand that the same principles may beapplied to other communication nodes in a communication system.

The process starts at step or module 800. In a step or module 805, aquality parameter such as a noise-and-interference level N_(own) _(—)_(link) at a receiving communication node such as the secondcommunication node 610 illustrated in FIG. 6 is acquired. Theacquisition may use a noise-and-interference level report transmitted bythe receiving communication node from an earlier round. Alternatively,the acquisition may subtract a path loss estimate (in dB) to thereceiving communication node from a noise-and-interference levelmeasurement (in dB) made at, for instance, the transmittingcommunication node such as the first communication node 605 illustratedin FIG. 6. In a step or module 810, another quality parameter such as areceived signal strength S_(own) _(—) _(link) at the receivingcommunication node such as the second communication node 610 illustratedin FIG. 6 is predicted. The prediction may use a received signalstrength from an earlier round. The prediction may be based on thepredicted noise-and-interference level and a constant, for example, apredicted noise-and-interference level +10 dB. If the method isimplemented with respect to step or module 735 illustrated in FIG. 7,the received signal strength may be estimated by subtracting a path lossestimate (in dB) to the intended receiving communication node resultingfrom the transmitter power level.

In a step or module block 815, the throughput TP_(own) _(—) _(link) of asingle/negotiated communication resource is predicted. For example, theprediction may employ a function log (1+SNIR), wherein SNIR is thepredicted signal-to-noise plus interference ratio. In an alternativeembodiment, a mapping function such as a modulation and coding scheme(“MCS”) table dependent on a predicted signal-to-noise ratio may beemployed. In one example embodiment, the throughput is estimated asTP_(own) _(—) _(link)=BW log₂(1+SNIR/c), where BW is the bandwidth ofthe communication or radio resource, and c is a predetermined constant(e.g., c=1.8). In a step or module 820, a summed throughput TP_(sum) ofall communication resources used for transmission is calculated. Afunction such as that employed in step or module 815 may be employed topredict SNIR. In a step or module 825, the number of communication linksn_(links) supported by the transmitting communication node is counted.In FIG. 6, while only a single communication link 615 is illustratedbetween the transmitting communication node (the first communicationnode 605) and the intended receiving communication node (the secondcommunication node 610), other communication nodes might be served iftransmitting communication node is an access point.

In a step or module block 830, a minimum throughput value TP_(min) forthe summed throughput is determined. The minimum throughput value may bea predetermined constant, for example, 100 kilobits-per-second (“kbps”)for every maintained communication link. In a step or module 835, thecalculated summed throughput is limited to not fall below the minimumthroughput value TP_(min) computed in the step or module 830. In a stepor module 840, the weighting factor W_(own) _(—) _(link) is determinedas a ratio of predicted resource throughput computed in the step ormodule 815 to the summed throughput computed in the step or module 835(e.g., W_(own) _(—) _(link)=TP_(own) _(—) _(link)/TP_(sum)). The methodends in a step or module 845.

Turning now to FIG. 9, illustrated is a flowchart of an embodiment ofgenerating an interference message M by a communication node (e.g., aninterfered communication node such as the third communication nodeillustrated in FIG. 6) in accordance with the principles of the presentinvention. The interference message may be received by a communicationnode preparing to transmit data (e.g., a transmitting communication nodesuch as the first communication node 605 illustrated in FIG. 6). Thetransmitting communication node receives the interference message fromthe interfered communication node including a weighting factorW_(interfered), and interference characteristics such as a signalstrength S_(interfered), and a noise-and-interference levelN_(interfered). For the purpose of clarity and in the spirit of anexemplary embodiment, the method that follows will be described from theperspective of an interfered communication node. Those skilled in theart, however, should understand that the same principles may be appliedto other communication nodes in a communication system.

The method begins in a step or module 900. In a step or module 905, aninterference characteristic such as a received signal strengthS_(interfered) on a communication or radio resource is determined at theinterfered communication node. In a step or module 910, anotherinterference characteristic such as a noise-and-interference levelN_(interfered) on the communication resource is determined by theinterfered communication node. Alternatively, the determination of theinterference characteristics may subtract a path loss estimate (in dB)between the interfered communication node and the transmittingcommunication node.

In a step or module 915, a weighting factor W_(interfered) isdetermined. The weighting factor may be determined based on signalstrength, summed throughput, and relative importance of thecommunication resource. In a step or module 917, the weighting factor isconstrained with a constraint function. A constraint function may beconstructed as described hereinabove with reference to FIG. 6. In a stepor module 920, a signal strength, noise-and-interference level, andweighting factor are formatted and encoded into the interferencemessage. Encoding the weighting factor may include quantization, whichmay be performed, without limitation, on a logarithmic scale (e.g., alogarithmic scale using three bits). In a step or module 925, theinterference message is transmitted to a transmitting communication nodeand the method ends in a step or module 930.

In another embodiment, only limited changes in a transmitter power levelare allowed for a communication resource when an interferedcommunication node has been detected by a communication node thatprepares to transmit a message. Limiting changes to a transmitter powerlevel prevents “overshooting” a change in the transmitter power levelwhen a large change would result in an excessive change in a weightingfactor. Limiting the rate of increase in a transmitter power level inthe presence of an interfered communication node also improves systemrobustness when more than one communication node receives aninterference message and decides to increase a transmitter power level.

Turning now to FIG. 10, illustrated is a flowchart of an embodiment of amethod of selecting a transmitter power level for a message by acommunication node (e.g., a transmitting communication node such as thefirst communication node 605 illustrated in FIG. 6) that may interferewith another communication node (e.g., an interfered communication nodesuch as the third communication node 620 illustrated in FIG. 6) inaccordance with the principles of the present invention. The methodstarts in a step or module 1000. In a step or module 1005, thetransmitting communication node determines whether interference messageshave been received from interfered communication nodes. If nointerference message has been received, the method ends in a step ormodule 1025.

If at least one interference message has been received, the transmittingcommunication node finds the highest reported weighting factor W_(max)of all the received reports in a step or module 1010. In a step ormodule 1015, the transmitting communication node compares the highestreported weight factor W_(max) against a threshold. If the highestreported weighting factor W_(max) is not above a threshold, the methodends in the step or module 1025. If the highest reported weightingfactor W_(max) is above the threshold, the transmitting communicationnode limits the increase in transmitter power level for a message over aprevious processing round to the threshold, and the method ends in thestep or module 1025. The change in transmitter power level may berestricted to an increase in transmitter power level. The maximum changein transmitter power level (i.e., the threshold) may be a predeterminedconstant. The maximum change in transmitter power level at thetransmitting communication node may depend on the highest reportedweighting factor W_(max), for example, the maximum change may be limitedto the value 10·(1−W_(max)) dB, with W_(max) a value falling in therange [0, 1]. In an alternative embodiment, if the highest reportedweighting factor W_(max) is above the threshold, the transmittingcommunication node limits a change in transmitter power level comparedto a previous processing round to the threshold in a step or module1020, and the method ends in a step or module 1025.

Better fairness and system efficiency can thus be obtained with theintroduced improvements to interference-aware scheduling. This can beaccomplished with reasonable additional signaling overhead overconventional interference-aware scheduling. If the reported weightingfactors, etc., are reported using a sufficient number of bits to providea low level of quantization error, a communication node preparing totransmit can come close to an optimum solution using a single reportingcycle. In such circumstances there would generally be no need torepeatedly report interference data and iterate. The process does notrequire a distinction between communication nodes such as user equipmentand an access point/base station node. It can be implemented incommunication nodes that support devices that communicate through anaccess point/base station as well as D2D communication links.

Thus, an apparatus, method and system are introduced herein to control atransmitter power level to manage interference between communicationnodes in a communication system. In one embodiment, an apparatus (e.g.,embodied in a communication node such as a user equipment) includes aprocessor and memory including computer program code. The memory and thecomputer program code are configured to, with the processor, cause theapparatus to receive an interference message including a reportedinterference characteristic (e.g., at least one of a reported signalstrength and a reported noise-and-interference level) associated with acommunication resource employed by an interfered communication node anda reported weighting factor indicating an importance of thecommunication resource to the interfered communication node. The memoryand the computer program code are also configured to, with theprocessor, cause the apparatus to generate a message for a receivingcommunication node employing the communication resource, and select atransmitter power level for the message as a function of the reportedinterference characteristic and the reported weighting factor. Thetransmitter power level may be a function of a transmitter power levelrange including a finite set of power levels, may be limited from aprevious transmitter power level.

In a related embodiment, the memory and the computer program code arefurther configured to, with the processor, cause the apparatus topredict a throughput over the communication resource to the interferedcommunication node as a function of a transmitter power level range,determine a weighting factor as a function of the reported weightingfactor, apply the weighting factor to the throughput to obtain aweighted throughput, and select the transmitter power level by applyingthe transmitter power level range to a utility function including theweighted throughput. In some cases, the weighting factor may equal thereported weighting factor.

In another related embodiment, the memory and the computer program codeare further configured to, with the processor, cause the apparatus todetermine a quality parameter of the communication resource to thereceiving communication node, predict a throughput over thecommunication resource to the receiving communication node as a functionof the quality parameter and a transmitter power level range, determinea weighting factor as a function of the throughput, apply the weightingfactor to the throughput to obtain a weighted throughput, and select thetransmitter power level by applying the transmitter power level range toa utility function including the weighted throughput. In an alternative,but related embodiment, the memory and the computer program code arefurther configured to, with the processor, cause the apparatus todetermine a quality parameter of the communication resource to thereceiving communication node, predict a throughput over thecommunication resource to the receiving communication node as a functionof the quality parameter and a transmitter power level range, predict asummed throughput over all communication resources employable by theapparatus, determine a weighting factor as a function of the throughputand the summed throughput, apply the weighting factor to the throughputto obtain a weighted throughput, and select the transmitter power levelby applying the transmitter power level range to a utility functionincluding the weighted throughput.

In another aspect, an apparatus (e.g., embodied in a communication nodesuch as a user equipment) includes a processor and memory includingcomputer program code. The memory and the computer program code areconfigured to, with the processor, cause the apparatus to determine aninterference characteristic (e.g., at least one of a signal strength anda noise-and-interference level) associated with a communication resourceemployed by the apparatus, and determine a weighting factor indicatingan importance of the communication resource to the apparatus. The memoryand the computer program code are also configured to, with theprocessor, cause the apparatus to format the interference characteristicand the weighting factor into an interference message for transmissionto a communication node. The memory and the computer program code arefurther configured to, with the processor, cause the apparatus toconstrain the weighting factor in accordance with a constraint function,which may be dependent on a number of communication nodes connected tothe apparatus. The memory and the computer program code are furtherconfigured to, with the processor, cause the apparatus to transmit theinterference message over the communication resource to thecommunication node. The interference characteristic may be determined inaccordance with a path loss to the communication node, and may beemployable to ascertain a throughput over the communication resource.Although the apparatus, method and system described herein have beendescribed with respect to cellular-based communication systems, theapparatus and method are equally applicable to other types ofcommunication systems such as a WiMax communication system.

Program or code segments making up the various embodiments of thepresent invention may be stored in a computer readable medium ortransmitted by a computer data signal embodied in a carrier wave, or asignal modulated by a carrier, over a transmission medium. For instance,a computer program product including a program code stored in a computerreadable medium may form various embodiments of the present invention.The “computer readable medium” may include any medium that can store ortransfer information. Examples of the computer readable medium includean electronic circuit, a semiconductor memory device, a read only memory(“ROM”), a flash memory, an erasable ROM (“EROM”), a floppy diskette, acompact disk (“CD”)-ROM, an optical disk, a hard disk, a fiber opticmedium, a radio frequency (“RF”) link, and the like. The computer datasignal may include any signal that can propagate over a transmissionmedium such as electronic communication network communication channels,optical fibers, air, electromagnetic links, RF links, and the like. Thecode segments may be downloaded via computer networks such as theInternet, Intranet, and the like.

As described above, the exemplary embodiment provides both a method andcorresponding apparatus consisting of various modules providingfunctionality for performing the steps of the method. The modules may beimplemented as hardware (embodied in one or more chips including anintegrated circuit such as an application specific integrated circuit),or may be implemented as software or firmware for execution by acomputer processor. In particular, in the case of firmware or software,the exemplary embodiment can be provided as a computer program productincluding a computer readable storage structure embodying computerprogram code (i.e., software or firmware) thereon for execution by thecomputer processor.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. For example,many of the features and functions discussed above can be implemented insoftware, hardware, or firmware, or a combination thereof. Also, many ofthe features, functions and steps of operating the same may bereordered, omitted, added, etc., and still fall within the broad scopeof the present invention.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

1.-40. (canceled)
 41. An apparatus, comprising: a processor; and memoryincluding computer program code, said memory and said computer programcode configured to, with said processor, cause said apparatus to performat least the following: receive an interference message including areported interference characteristic associated with a communicationresource employed by an interfered communication node and a reportedweighting factor indicating an importance of said communication resourceto said interfered communication node; generate a message for areceiving communication node employing said communication resource; andselect a transmitter power level for said message as a function of saidreported interference characteristic and said reported weighting factor.42. The apparatus as recited in claim 41, wherein said memory and saidcomputer program code are further configured to, with said processor,cause said apparatus to predict a throughput over said communicationresource to said interfered communication node and select saidtransmitter power level for said message as a function of saidthroughput.
 43. The apparatus as recited in claim 41, wherein saidmemory and said computer program code are further configured to, withsaid processor, cause said apparatus to: predict a throughput over saidcommunication resource to said interfered communication node as afunction of a transmitter power level range; determine a weightingfactor as a function of said reported weighting factor; apply saidweighting factor to said throughput to obtain a weighted throughput; andselect said transmitter power level by applying said transmitter powerlevel range to a utility function including said weighted throughput.44. The apparatus as recited in claim 43, wherein said weighting factorequals said reported weighting factor.
 45. The apparatus as recited inclaim 41, wherein said memory and said computer program code are furtherconfigured to, with said processor, cause said apparatus to determine aquality parameter of said communication resource to said receivingcommunication node and select said transmitter power level for saidmessage as a function of said quality parameter.
 46. The apparatus asrecited in claim 41, wherein said memory and said computer program codeare further configured to, with said processor, cause said apparatus to:determine a quality parameter of said communication resource to saidreceiving communication node; predict a throughput over saidcommunication resource to said receiving communication node as afunction of said quality parameter; and select said transmitter powerlevel for said message as a function of said throughput.
 47. Theapparatus as recited in claim 41, wherein said memory and said computerprogram code are further configured to, with said processor, cause saidapparatus to: determine a quality parameter of said communicationresource to said receiving communication node; predict a throughput oversaid communication resource to said receiving communication node as afunction of said quality parameter and a transmitter power level range;determine a weighting factor as a function of said throughput; applysaid weighting factor to said throughput to obtain a weightedthroughput; and select said transmitter power level by applying saidtransmitter power level range to a utility function including saidweighted throughput.
 48. The apparatus as recited in claim 41, whereinsaid memory and said computer program code are further configured to,with said processor, cause said apparatus to: determine a qualityparameter of said communication resource to said receiving communicationnode; predict a throughput over said communication resource to saidreceiving communication node as a function of said quality parameter anda transmitter power level range; predict a summed throughput over allcommunication resources employable by said apparatus; determine aweighting factor as a function of said throughput and said summedthroughput; apply said weighting factor to said throughput to obtain aweighted throughput; and select said transmitter power level by applyingsaid transmitter power level range to a utility function including saidweighted throughput.
 49. The apparatus as recited in claim 41, whereinsaid reported interference characteristic comprises at least one of areported signal strength and a reported noise-and-interference level forsaid communication resource employed by said interfered communicationnode.
 50. The apparatus as recited in claim 41, wherein said transmitterpower level is function of a transmitter power level range including afinite set of power levels.
 51. The apparatus as recited in claim 41,wherein a change of said transmitter power level is limited from aprevious transmitter power level.
 52. A method, comprising: receiving aninterference message including a reported interference characteristicassociated with a communication resource employed by an interferedcommunication node and a reported weighting factor indicating animportance of said communication resource to said interferedcommunication node; generating a message for a receiving communicationnode employing said communication resource; and selecting a transmitterpower level for said message as a function of said reported interferencecharacteristic and said reported weighting factor.
 53. The method asrecited in claim 52, further comprising predicting a throughput oversaid communication resource to said interfered communication node andselecting said transmitter power level for said message as a function ofsaid throughput.
 54. An apparatus, comprising: a processor; and memoryincluding computer program code, said memory and said computer programcode configured to, with said processor, cause said apparatus to performat least the following: determine an interference characteristicassociated with a communication resource employed by said apparatus;determine a weighting factor indicating an importance of saidcommunication resource to said apparatus; and format said interferencecharacteristic and said weighting factor into an interference messagefor transmission to a communication node.
 55. The apparatus as recitedin claim 54, wherein said memory and said computer program code arefurther configured to, with said processor, cause said apparatus toconstrain said weighting factor in accordance with a constraintfunction.
 56. The apparatus as recited in claim 55, wherein saidconstraint function is dependent on a number of communication nodesconnected to said apparatus.
 57. The apparatus as recited in claim 54,wherein said memory and said computer program code are furtherconfigured to, with said processor, cause said apparatus to determinesaid interference characteristic in accordance with a path loss to saidcommunication node.
 58. The apparatus as recited in claim 54, whereinsaid interference characteristic comprises at least one of a signalstrength and a noise-and-interference level for said communicationresource employed by said apparatus.
 59. The apparatus as recited inclaim 54, wherein said interference characteristic is employable toascertain a throughput over said communication resource.
 60. Theapparatus as recited in claim 54, wherein said memory and said computerprogram code are further configured to, with said processor, cause saidapparatus to transmit said interference message over said communicationresource to said communication node.